Binary logic gates implement logical operations on logic inputs to produce a logic output. The logic level (or state) of each logic input and output is either 0 (i.e., low) or 1 (i.e. high). In electrical systems, the logic level of an input or output is represented by its voltage level where typically a low voltage represents a logic 0 and a high voltage represents a logic 1. Similarly, prior art optical systems represent logic levels based on the intensity of the input/output electromagnetic wave. The only polarization-based logic level representation disclosed in the prior art utilizes a parallel/horizontal polarized electromagnetic wave, which has a relative polarization angle of zero, and a perpendicular/vertical polarized electromagnetic wave, which has a relative polarization angle of 90°, to represent the two logic levels in an optical system.
Optical gates that use intensity-based representations of logic levels to perform logical operations require regeneration of the output electromagnetic wave prior to cascading these gates. Additionally, existing optical gates include costly components such as uniaxial crystals, nonlinear optical elements, and semiconductor-type photo-detectors. Still further, prior art optical gates are inefficient in that they implement complicated parallel procedures and do not operate at optimal speed.
Accordingly, there is a need for an optical gate that uses a polarization-based logic level representation based on any polarization angle of an electromagnetic wave to perform logical operations in a cost effective and computationally simplified manner.